It has long been desirable that telephone instruments, provided with the usual lowspeaking device (conventional receiver in the handset), have the capability of having added thereto an additional speech device by means of a simple connection. An example of such an additional speech device is a loudspeaking element, the main handset and so on. In presently known telephone as, for example, "ERICOVOX" this can be carried out by a connection via an additional spring set.
In the presently developed telephone "DIAVOX" described in, for example, "Ericsson Review" No 3, 1977 (pages 112-113) an additional speech device for a loudspeaking function is provided in the instrument, a connection arrangement being required to achieve such connection between the two telephone functions.